A class of coupled-multiline quasi-elliptic-type balanced diplexer device with closely spaced channels and its balanced coupling-routing-diagram formalism to simultaneously model its differential- and common-mode operation are reported. It employs third-order combline-type bandpass filters (BPFs) in its filtering channels, whose resonating lines are connected at one of their extremes to the symmetry plane of the balanced-circuit structure (i.e., virtual grounds for the differential mode), along with a multiextracted-pole/coupled-multiline dual-band BPF junction and single-band BPF output cells. In differential-mode operation, the dual-band BPF junction adds one in-band pole to each diplexer channel and three transmission zeros (TZs) to both channels, whereas the single-band BPF output cells incorporate one in-band pole and two TZs in their corresponding channels. In this manner, increased-selectivity differential-mode BPF transfer functions for the diplexer channels when compared to those of its third-order combline-type BPFs are obtained. Grounded resistors are connected at the symmetry plane of the balanced diplexer for all the resonating lines of the combline-type BPFs, which become detuned with regard to the poles associated with the dual-band BPF junction and the single-band BPF output cells under common-mode excitation. This allows for high common-mode suppression levels in wide spectral ranges to be realized for both channels while maintaining the same TZs as in differential-mode operation. For practical-validation purposes, a 1.6-GHz/1.8-GHz microstrip prototype is manufactured and tested.

中文翻译：

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具有多提取极点结/输出部分的平衡准椭圆型梳状双工器

报告了一类具有紧密间隔通道的耦合多线准椭圆型平衡双工器设备及其平衡耦合路由图形式，以同时模拟其差模和共模操作。它在其滤波通道中采用三阶梳状带通滤波器 (BPF)，其谐振线在其极端之一连接到平衡电路结构的对称平面（即差模的虚拟接地），沿着具有多提取极/耦合多线双波段 BPF 结和单波段 BPF 输出单元。在差模操作中，双频 BPF 结为每个双工器通道添加一个带内极点，并为两个通道添加三个传输零点 (TZ)，而单频段 BPF 输出单元在其相应的通道中包含一个带内极点和两个 TZ。以这种方式，与三阶梳状线型 BPF 相比，双工器通道的选择性增加的差模 BPF 传递函数被获得。接地电阻器连接在平衡双工器的对称平面上，用于梳状 BPF 的所有谐振线，这些谐振线相对于与双频 BPF 结和单频 BPF 输出单元相关的极点失谐。 -模式激发。这允许在宽光谱范围内为两个通道实现高共模抑制水平，同时保持与差模操作相同的 TZ。出于实际验证目的，1.6-GHz/1.